You may have heard before that Cleopatra was born closer in time to the Space Shuttle (or Moon landing, or launch of the iPhone – basically today) than she did to the building of the pyramids. The first time you hear this it may seem odd. We have a tendency to compress ancient history, as if it were one time period. It is also difficult for modern people to imagine the incredibly deep history of humanity. Civilization has changed so much over the last 100 years, and 2000 years, that it is difficult to imagine thousands or even tens of thousands of years going by will relatively little change.
I was reminded of this by a recent news item – evidence now suggests that the middle stone age lasted 20,000 years longer than previously thought. To put this into context, the early stone age, with the most primitive stone tools, started about 2.6 million years ago and lasted until about 300,000 years ago. Don’t even try to wrap your head around 2.3 million years. This only counts the human genus, but stone tool use predates humans. From 300k to 30k year ago was considered the middle stone age, using a more sophisticated tool kit and tool production methods. The tool kit was more diversified and likely represented a greater range of activities for hunting and processing food.
Then around 50,000 years ago the later stone age tools started appearing. This was still a more sophisticated too kit, designed to be smaller and more mobile and likely reflected a change in lifestyle. The middle stone age was replaced by the later stone age by 30,000 years ago – or so we thought. New evidence suggests that middle stone age culture persisted until about 11,000 years ago in isolated populations in Africa.
This persistence likely reflects the fact that prehistoric populations were far more isolated than more modern populations. It may also simply reflect the persistence of culture. If these populations did not change their basic subsistence strategy, they would have had no reason to update their tool kit. Researchers hypothesize that changes in the environment allowed for easier migration corridors, causing cultural mixing and the final replacement of the last vestiges of middle stone age culture.
At 7000 years ago (5,000 BCE) there is the first evidence of copper smelting, which was a transition period (the Chalcolithic) to the bronze age, which started 3,300 BCE and lasted until 1,200 BCE. Metallurgy was clearly a huge innovation for humanity. The technology was also largely about temperature – how hot could they make their ovens. Copper has a relatively low melting point of 1084 C, which was achievable in the pottery kilns of the time. Eventually they figured out how to alloy copper with other metals, like tin (which has a melting point of only 232 C), making a metal, bronze, that is stronger than either element by itself.
For iron you need to get up to about 1,500 degrees (depending on type) so this required better oven technology. The iron age begins at different times in different regions, beginning by about 1,200 BCE and spreading everywhere by 500 BCE.
Historians have noted the overall pattern here, if you look at the time to transition to the next stage of technology: 2.3 million years, 270,000 years, 23,000 years, 2,000 years. There is wiggle room in the exact dating, as the recent news item indicates, because transitions occurred over time, with older technology persisting in regions or isolated populations sometimes for a relatively long time. But the overall pattern is pretty clear – each major transition occurred about one order or magnitude more quickly than the one before. If we consider technological development in the last 2,000 years this acceleration seems to be holding. It is more difficult to determine clear technological “ages” because there are many types of technology that are changing all the time. There is no longer one dominant toolkit that can determine the overall level of technology. But still, the pattern seems to be holding more or less.
This is one core premise of ideas like the Singularity. Kurzweil and others argue that this pattern will continue, until massive technology progress is happening so quickly the timeline for predicting or extrapolating future technology will shrink essentially to nothing, a singularity beyond which we cannot see. I don’t entire buy this premise, as I think other patterns start to intrude on the overall pattern of accelerating progress. The problem here is that we are trying to predict future patterns of change by extrapolating from past patterns, but this assumes that all the important forces will remain the same.
It is possible, however, that we may run up against practical limitations. While it is true that our knowledge and technological prowess may still be accelerating, the difficulty of the challenges we are trying to solve are also getting greater. So technology progress is different for different areas, depending on how mature the technology is and the difficulty of the challenge. For example, commercial jet travel is not any faster today than half a century ago. There are practical limitations to how fast a jet can go, and it will take a major shift to a new technology before that will change. Progress will happen, but it’s not really linear, and therefore it’s hard to extrapolate.
I would love to have access to an “Encyclopedia Galactica” and read the history of technological development of many different species to see what patterns tend to exist, looking back from a point far in our technological future. That’s unlikely to happen, so we will have to content ourselves will trying to extrapolate from past patterns, but this has significant caveats.
Right now we are in the middle of the broad brushstrokes of technological history (although this may be an artifact of our perspective). We tend to grossly mentally underestimate the depth of history, because it is simply outside of our experience. Taking millions of years for a noticeable shift in technology is simply beyond our perspective. The same is likely true of our future – we would have a hard time imaging the pace of future technological progress. We may be at the inflection point of history. At the same time, future technology may hit significant plateaus dictated by the laws of physics and issues of practicality. I guess we’ll have to wait and see.
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